Internal combustion engine with inlet and outlet valves

ABSTRACT

This invention relates to an internal combustion engine with intake and exhaust valves ( 6, 7 ) and one nozzle mount ( 4 ) per cylinder ( 2 ) for an injection nozzle ( 5 ) injecting fuel into a combustion chamber, the nozzle mount being connected to a fuel supply line ( 14 ) and a return oil line ( 19 ), the nozzle mount ( 1 ) being screwed into a first recess ( 13 ) in the cylinder head ( 1 ), and the cylinder head ( 1 ) exhibiting a second recess ( 17 ) approximately normal to an engine longitudinal plane ( 16 ) containing the cylinder axis ( 3 ), which second recess, extending from a first cylinder head longitudinal side wall ( 15   a ), intersects the first recess ( 13 ) approximately radially. In order to make possible a reliable fuel supply to the nozzle mount ( 4 ) with minimal space requirement and short fuel supply lines ( 14 ), the second recess ( 17 ) continues up to the second cylinder head longitudinal side wall ( 15   b ) lying opposite the first cylinder head longitudinal side wall ( 15   a ) and forms in this region the return oil drain.

This invention relates to an internal combustion engine with intakevalves and exhaust valves and, for each cylinder, one nozzle mountconnected to a fuel supply line and an overflow oil line for aninjection nozzle injecting fuel into a combustion chamber, the nozzlemount being inserted in a first recess of the cylinder head and thecylinder head exhibiting, approximately normally to an enginelongitudinal plane containing the cylinder axis, a second recess, which,starting from a first cylinder head longitudinal side wall, strikes thefirst recess approximately radially.

In internal combustion engines of the type stated at the outset, thereis scarcely any free space for the arrangement of the fuel supply linefur the central injection nozzle, especially when there are six cylinderhead bolts surrounding one cylinder each and four valves per cylinder.In order to keep the fuel supply line between a cam-actuated screw-inpump and the injection nozzle as short as possible, feeding into thecylinder head on a cylinder head longitudinal side is desirable. Thespace required therefor is, however, often already occupied by pushrods, breathing ducts, cylinder head bolts or the like.

U.S. Pat. No. 3,845,748 A shows such a lateral supply of fuel. Anyescaping fuel is returned to an overflow oil bore via a slot between thesupply bore and the fuel line. Such a solution is, however, costly and,because of a large number of seals, susceptible to malfunctions.

It is an object of the present invention to find, for an internalcombustion engine of the type stated at the outset, a fuel supply linearrangement, favorable in terms of installation and maintenance as wellas reliable and space-saving, for a lateral fuel supply.

According to the invention, this object is achieved by virtue of thefact that the second recess continues up to the second cylinder headlongitudinal side wall lying opposite the first cylinder headlongitudinal side wall and forms the overflow oil drain in this region.This makes possible, on the one hand, very simple fabrication and, onthe other hand, simple installation and removal.

The recess for the overflow oil drain preferably opens into an overflowoil line running in the engine longitudinal direction.

An especially favorable design, particularly with respect to thermalstresses, is achieved by virtue of the fact that the fuel supply line isled in the second recess from the first cylinder head longitudinal sidewall up to a radial inlet port of the nozzle mount, preferably beingclamped in place by a thrust piece made in the form of a hollow screwand screwed into the second recess.

The thrust piece is preferably screwed into the cylinder head abouthalfway between the first cylinder head longitudinal side wall and thenozzle mount and is sealed off from the cylinder head between thethreaded connector and the nozzle mount by a seal, preferably an O-ringseal, the sealed-off overflow oil slot formed by the thrust piece andthe cylinder head being in flow connection to the overflow oil line.Further, there can be an additional O-ring seal in the region of thefirst cylinder head longitudinal side wall to seal the thrust piece offfrom the cylinder head. In this way, reliable sealing of the thrustpiece and the fuel supply line is achieved, any fuel that may leak intothe nozzle mount in the opening region of the fuel supply line being fedinto the overflow oil system.

In an especially preferred development of the invention, the axis of thesecond recess, in the region between the threaded connector and thefirst cylinder head longitudinal side wall, intersects the axis of acylinder head bolt hole formed into the cylinder head between the thrustpiece and the cylinder head gasket surface. During assembly, thecylinder head bolt is first screwed into this cylinder head bolt hole,and then the fuel supply line can be connected to the thrust piece onthe nozzle mount. In this way, the bearing surface of the cylinder headbolt hole for the head surface of the cylinder head bolt is sunk underthe second recess.

The invention is explained in more detail on the basis of the Figures.

FIG. 1 shows a cross section through the cylinder head according to theinvention along line I—I in FIG. 2.

FIG. 2 shows a top view of the cylinder head.

The cylinder head 1 exhibits, for each cylinder 2, a nozzle mount 4arranged in the region of the cylinder axis 3 for an injection nozzle 5opening centrally into the cylinder 2, as well as two intake valves 6and two exhaust valves 7 per cylinder 2. Intake ducts 6 a or exhaustducts 7 a, which issue from flange surfaces 6 b or 7 b, respectively, onthe same longitudinal side 8 of the internal combustion engine, open tothe intake valves 6 or exhaust valves 7, respectively. Two cylinder headbolts 11, 12 enclosing the cylinder 2 are arranged in each of twolocations: in the region of engine transverse planes 9 to either side ofeach cylinder 2 and in an engine transverse plane 10 running through thecylinder axis 3.

The nozzle mount 4 is screwed into the cylinder head 1 in a first recess13 coaxially with the cylinder axis 3. Access to the nozzle mount 4 iseffected by a fuel supply line 14, which opens into the cylinder head 1via the first cylinder head longitudinal side wall 15 a lying oppositethe intake flange surfaces 6 b and exhaust flange surfaces 7 b. The fuelsupply line 14 is led through a second recess 17 arranged normally tothe engine longitudinal plane 16, in the transverse plane 10, to aradial inlet port 25 of the nozzle mount 4. The opening of the fuelsupply line 14 is identified by the number 18.

The second recess 17, starting from the cylinder head longitudinal sidewall 15 a, runs normally to the first recess 13, crosses said firstrecess radially, continues diametrically to the opening 18 into thefirst recess 13 on the other side of the engine longitudinal plane 16 inthe cylinder head 1 as recess 19 for the overflow oil drain, and finallyopens into an overflow oil line 20 in the region of the second cylinderhead longitudinal side wall 15 b. The fuel supply line 14 is fed by ascrew-in pump, not shown in more detail, which is actuated via a cam,not further shown, of a camshaft. The cylinder head 1 is closed offabove by a rocker-arm housing, identified by reference number 23, whichaccommodates a valve operating mechanism, not shown in more detail, theintake flange surface 6 b being formed by the rocker-arm housing 23.

The opening 18 of the fuel supply line 14 is pressed against the inletport 25 of the nozzle mount 4 by a thrust piece 24, made in the form ofa hollow screw, which is screwed into the second recess 17. The thrustpiece 24 exhibits an annular elastic pressure element 26. Between thethreaded connector 27, which is arranged about halfway between the firstcylinder head longitudinal side wall 15 a and the nozzle mount 4, andthe pressure element 26, there is an O-ring seal 28 for sealing thethrust piece 24 off from the cylinder head 1. If there is a leak of fuelbetween the opening 18 and the inlet port 25 of the nozzle mount 4 andfuel gets into the overflow oil slot 29 between thrust piece 24 andcylinder head 1, further penetration into the valve operatingcompartment 22 a is blocked by the O-ring seal 28. The overflow oil slot29 is connected to the overflow oil duct 19, so that the leaked liquidcan be returned to the overflow oil system via the overflow oil line 20.The reference number 33 identifies an overflow oil escape port of thenozzle mount 4, which is connected to the recess 19 for the overflow oildrain.

As FIG. 1 shows, the thrust piece 24 is arranged over the bearingsurface 11 c of a cylinder head bolt hole 11 b for the head surface lidof a cylinder head bolt 11, the axis 11 a of which cylinder head boltintersects the axis 17 a of the second recess 17. The cylinder head bolt11 lying under the thrust piece 24 is made shorter than the othercylinder head bolts 12. Naturally, actuation of the cylinder head bolt11 is possible only when the thrust piece 24 is removed. Theinstallation and removal of the thrust piece 24 in the cylinder head 1and its reliable sealing off is, however, possible in a problem-freemanner by virtue of the design described.

In the region of the first cylinder head longitudinal side wall 15 a,there is a further seal 30 between thrust piece 24 and cylinder head 1,which further seal seals the operating space 22 a off from thesurroundings.

As FIG. 2 shows, the thrust piece 24 with fuel supply line 14 isarranged between the bores 31 a and 32 a for push rods, not furthershown, as well as between the two intake valves 6 over the cylinder headbolt 11 in the engine transverse plane 10 in the cylinder head 1. Inthis way, optimal utilization of the available free space and thus avery compact design of the cylinder head 1 is possible with extremelyshort fuel supply lines 14.

What is claimed is:
 1. An internal combustion engine comprising: acrankcase (2 a) including a plurality of parallel cylinders (2) whoseaxes (3) define an engine longitudinal plane (16), a cylinder head (1)secured to said crankcase (2 a) in covering relation to said cylinders(2) including lateral opposite longitudinal side walls (15 a, 15 b); aninjection nozzle holder bore (13) for each cylinder (2), an injectionnozzle holder (4) in each nozzle holder bore (13) a fuel line bore (17)formed in said cylinder head (1) normal to said nozzle holder bore (13)and said engine longitudinal plane (16), said fuel line bore (17)extending from one of said longitudinal side walls to one side of saidnozzle holder bore (13) thereby forming an opening for a fuel line tosaid injection nozzle holder and an overflow fuel drain passage (19)extending from the side of said nozzle holder bore (13) diametricallyopposite to said one side and in alignment with said fuel line bore(17).
 2. The internal combustion engine of claim 1 and furthercomprising a cylinder head bolt hole (11 b) formed in said cylinder head(1) on an axis (11 a) intersecting the axis (17 a) of said fuel linebore (17).
 3. The internal combustion engine of claim 1 and furthercomprising an overflow fuel conduit (20) extending along said otherlongitudinal side wall (15 b), said overflow drain passage (19)connecting to said overflow fuel conduit (20).
 4. The internalcombustion engine of claim 3 wherein said nozzle holder (4) includes aradial inlet port (25) and further comprising a fuel line (14) disposedin said fuel line bore (17) and connected to said radial inlet port(25).
 5. The internal combustion engine of claim 1 wherein said nozzleholder (4) includes a radial port (25) and further comprising a fuelline (14) disposed in said fuel line bore (17) and connected to saidradial inlet port (25).
 6. The internal combustion engine of claim 5wherein said fuel line bore (17) includes a threaded part and furthercomprising a thrust sleeve (24) having a threaded portion (27) inthreaded engagement with said threaded part, said thrust sleeve (24)being in thrust engagement with said fuel line (14) whereby said duelline (14) is held in thrust transmitting engagement with said radialinlet port (25) of said nozzle holder (4).
 7. The internal combustionengine of claim 6, wherein said threaded part of said fuel line bore(17) is approximately midway between said one longitudinal side wall (15a) of said cylinder head (1) and said nozzle holder (4).
 8. The internalcombustion engine of claim 6 and further comprising a first O-ring seal(28) sealing said thrust sleeve (24) in relation to said cylinder head(1) between said threaded portion (27) and said nozzle holder (4)thereby defining a sealed off overflow fuel slot (29) between saidthrust sleeve (24) and said cylinder head (1), said overflow fuel slot(29) being in fluid communication with said overflow fuel drain passage(19).
 9. The internal combustion engine of claim 7 and furthercomprising a second O-ring seal between said thrust sleeve (24) and saidcylinder head (1) at said one cylinder head longitudinal side wall (15a).
 10. The internal combustion engine of claim 7 wherein said cylinderhead (1) includes a cylinder head gasket surface (1 a) and furthercomprising a cylinder head bolt hole (11 b) in said cylinder head (1)extending to said cylinder head gasket surface (1 a), the axis (11 a) ofsaid cylinder head bolt hole (11 b) intersecting the axis (17 a) of saidfuel line bore (17).
 11. An internal combustion engine comprising: acrankcase (2 a) including a plurality of parallel cylinders (2) whoseaxes (3) define an engine longitudinal plane (16), a cylinder head (1)secured to said crankcase (2 a) in covering relation to said cylinder(2) including laterally opposite longitudinal side walls (15 a, 15 b), ahead gasket surface (1 a) at its bottom, a central part including aninjection nozzle holder bore (13) for each cylinder (2) extending fromthe top of said cylinder head to said head gasket surface, an upwardlyopen cavity extending downwardly from its top between one of saidlongitudinal side walls (15 a, 15 b) and said central part, an injectionnozzle holder (4) in each nozzle holder bore (13) including a radialport (25), a fuel line bore (17) formed in said cylinder head (1) normalto said nozzle holder bore (13) and said engine longitudinal plane (16),said fuel line bore (17) having a first segment extending through saidone longitudinal side wall and a second segment extending into saidcentral part to one side of said nozzle holder bore (13), said fuel linebore in said central part including a threaded part, a fuel line (14)extending through said fuel line bore and connected to said radial port(25), a thrust sleeve (24) extending (22) through said first segment ofsaid fuel line bore (17), across said cavity and into said secondsegment of said fuel line bore (17), said thrust sleeve (24) including athreaded portion (27) in threaded engagement with said threaded part,said thrust sleeve (24) being in thrust transmitting engagement withsaid fuel line (14) whereby said fuel line (14) is held in thrusttransmitting engagement with said radial inlet port (25) of said nozzleholder (4) and, a cylinder head bolt hole (11 b) extending from thebottom of said cavity to said cylinder head gasket surface (1 a), saidcylinder head bolt hole (11 b) being vertically spaced directly belowsaid thrust sleeve (24).